/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
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 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
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 * file and include the License file at packager/legal/LICENSE.txt.
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 * GPL Classpath Exception:
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 */

package org.glassfish.jsondemos.jaxrs;

import javax.json.Json;
import javax.json.stream.JsonParser;
import javax.json.stream.JsonParser.Event;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.StreamingOutput;
import java.io.*;
import java.net.URL;
import java.util.Iterator;

/**
 * Filters JSON from twitter search REST API
 *
 * @author Jitendra Kotamraju
 */
@Path("/parser")
public class ParserResource {

    @GET
    @Produces("text/plain")
    public StreamingOutput doGet() {
        return new StreamingOutput() {
            public void write(OutputStream os) throws IOException {
                writeTwitterFeed(os);
            }
        };
    }

    /**
     * Parses JSON from twitter search REST API
     *
     * ... { ... "from_user" : "xxx", ..., "text: "yyy", ... } ...
     *
     * then writes to HTTP output stream as follows:
     *
     * xxx: yyy
     * --------
     */
    private void writeTwitterFeed(OutputStream os) throws IOException {
        URL url = new URL("http://search.twitter.com/search.json?q=%23java");
        try(InputStream is = url.openStream();
            JsonParser parser = Json.createParser(is);
            PrintWriter ps = new PrintWriter(new OutputStreamWriter(os, "UTF-8"))) {

            while(parser.hasNext()) {
                Event e = parser.next();
                if (e == Event.KEY_NAME) {
                    if (parser.getString().equals("from_user")) {
                        parser.next();
                        ps.print(parser.getString());
                        ps.print(": ");
                    } else if (parser.getString().equals("text")) {
                        parser.next();
                        ps.println(parser.getString());
                        ps.println("---------");
                    }
                }
            }
        }
	}

}
